In cubic integration, a plurality of substrates are stacked on top of one another and firmly connected to one another. The individual substrates thereby each respectively have integrated circuits, sensor-actuator arrangements and/or planar passive components. The individual substrates can thereby be manufactured in different technologies. The components contained in the various substrates are electrically connected to one another by vertical contacts.
The substrates are first manufactured independently of one another in the manufacture of such a cubically integrated circuit arrangement. The substrates manufactured independently of one another are then extremely thinned, down to approximately 10 .mu.m. The thinned substrates have their front side and back side provided with electrical contacts and are arranged above one another such that mechanical and thermal demands are also met in addition to the electrical demands of the circuit arrangement. The circuit arrangement must be mechanically stable, whereby extreme mechanical stresses should be avoided. Further, the dissipated heat that increases with increasing integration must be eliminated.
In a reference Y. Hayashi et al, Symp. on VLSI Technol. (1990) pages 95 ff it is disclosed that the processed front side of a substrate be protected in cubic integration during thinning and during the further process steps in that a solid carrier layer of, for example, silicon or quartz is glued onto the front side of the substrate. The substrate is then thinned and provided with contacts proceeding from the back side. Subsequently, the thinned substrate is applied onto a further substrate and is firmly connected thereto in a bonding process. After the bonding process, the carrier layers must in turn be stripped off without damaging the components in the substrates or undoing the connection between the substrates. A testing of the components in the thinned substrate is only possible proceeding from the back side before the bonding process since the carrier layer covers the front side and thinned substrates do not withstand standard testing procedures without stabilizing carrier layer. Both-sided contacting, however, is required when testing non-autonomous ICs such as, for example, for the inner levels of a memory stack. Numerous process steps are required for producing contacts and metallization structures on the back side of the thinned substrates.